Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B9/00—Making granules
  • B29B9/16—Auxiliary treatment of granules
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B7/00—Mixing; Kneading
  • B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
  • B29B7/58—Component parts, details or accessories; Auxiliary operations
  • B29B7/582—Component parts, details or accessories; Auxiliary operations for discharging, e.g. doors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B7/00—Mixing; Kneading
  • B29B7/80—Component parts, details or accessories; Auxiliary operations
  • B29B7/82—Heating or cooling
  • B29B7/826—Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B9/00—Making granules
  • B29B9/02—Making granules by dividing preformed material
  • B29B9/06—Making granules by dividing preformed material in the form of filamentary material, e.g. combined with extrusion
  • B29B9/065—Making granules by dividing preformed material in the form of filamentary material, e.g. combined with extrusion under-water, e.g. underwater pelletizers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
  • B29C41/003—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor characterised by the choice of material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
  • B29C71/02—Thermal after-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B9/00—Making granules
  • B29B9/16—Auxiliary treatment of granules
  • B29B2009/166—Deforming granules to give a special form, e.g. spheroidizing, rounding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
  • B29C71/02—Thermal after-treatment
  • B29C2071/022—Annealing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
  • B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
  • B29C41/04—Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
  • B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
  • B29C41/18—Slush casting, i.e. pouring moulding material into a hollow mould with excess material being poured off
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/25—Solid
  • B29K2105/251—Particles, powder or granules
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2973—Particular cross section
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2991—Coated
  • Y10T428/2998—Coated including synthetic resin or polymer

Definitions

• This invention relates generally to materials and methods for manufacturing plastic parts and, more particularly, for manufacturing plastic shells or skins by applying plastic particles to a heated forming surface.
• U.S. Patent No. 5,998,030 recites that individual particles formed by the high intensity mixer process have a roughened surface with fissures and cracks therein. Further, the '030 Patent goes on to recite that the use of such irregularly shaped particles in processing that includes feeding the particles to a point of use and casting the particles on a heated mold to melt flow the particles and cool them to form thin plastic shells presents several problems. In the case of slush molding, the particles are retained in a powder box that is rotated to direct an excess charge of material into a mold cavity. Such thermoplastic, irregular particles do not flow smoothly from all corners of a powder box.
• such particles do not smoothly flow into all parts of complex shaped molds of the type having tight return passages and very small mold surface features that simulate features such as leather grains, stitching or the like.
• it is necessary to vibrate the powder box and molds during the various processing steps so that the particles will flow against heated mold surfaces so as to melt and form a skin or shell shape corresponding to the shape of the heated mold surface.
• the irregular shape also produces an uneven build-up of material on the heated mold surface such that the particles do not melt and flow uniformly against the heated mold surface.
• the resultant cast part can have an irregular backside surface (i.e. opposite the mold surface).
• thermoplastic microsphere comprising thermoplastic resin melt blended with pigment, said pigment comprising less than 5% by weight of said blend, said microspheres having an outer diameter in the range of 0.178 mm to 1.016 mm.
• a plastic particle comprising a plastic material and having an integral protruding ring section disposed on its outer surface.
• the ring may be continuous or non-continuous around a perimeter of the plastic particle.
• the particles optionally have an outer diameter in the range of 0J78 millimeters to 1.016 millimeters.
• a method of forming a plastic particle comprising a plastic material and having at least one integral protruding ring disposed on its outer surface is provided.
• the method comprises the steps of providing a plastic particle capable of forming at least one protruding ring on the outer surface of the plastic particle and heating the plastic particle until at least one integral protruding ring is disposed on the outer surface of the particle.
• the method may also include the step of cooling the plastic particle after the ring is disposed on the outer surface of the particle.
• the method may also include the steps of providing a die with at least one die hole, extruding the plastic material through the die hole, severing the extrudate to create a plastic particle, and cooling the plastic particle before the ring is disposed on the outer surface of the particle.
• a method of forming a plastic article from a plurality of plastic particles is provided.
• the method comprises the steps of providing a plurality of plastic particles, providing a forming surface for forming the plastic article, applying the plurality of plastic particles on the forming surface, heating the plastic particles while the plastic particles are disposed on the forming surface; and flowing the plastic particles while the plastic particles are disposed on the forming surface to form at least one integral protruding ring on the outer surface of at least one particle.
• the method may also include the steps of continuing to flow the plastic particles while the plastic particles are disposed in the forming surface to join the particles and form the plastic article, cooling the forming surface, and removing the molded article from the forming surface.
• the plastic article comprises the shell or skin of an interior trim panel for a motor vehicle.
• FIG. 1 is a side elevation view of an underwater thermoplastic pelletizer having an extruding die system incorporated therein and wherein the extruding die is shown in section and other parts of the pelletizer are broken away;
• FIG. 2 is a photomicrograph of the particle herein containing an integral protruding ring section;
• FIG. 3 is a schematic view of a plastic particle with a continuous ring structure according to the present invention;
• FIG. 4 is a schematic view of a plastic particle with a non-continuous ring structure according to the present invention;
• FIG. 5 is a diagrammatic view of apparatus used to practice a slush molding.
• the pelletizer die system basically comprises a transition device 14 that feeds molten plastic from a source (not shown), such as an extruder, through a passage 16 to the passage 36 of die 12. From passage 36, the plastic enters cavities 52 and then die holes 42 of die plate 46. Upon exiting die holes 42, a multibladed cutter 18 that is driven through a shaft 20 by a motor 22 severs the plastic extruded from the die holes 42 in the die plate 46 into particles.
• a water circulating system generally designated at 26 includes a water box 28 enclosing the cutter 18 and the face 30 of the die 12. Cooled water is delivered to the water box 28 by a feed line fitting 32 where it acts to solidify the extruded plastic for cutting and wherein the particles that are cut in such an underwater environment are then conveyed along with the now warmed water from the water box by a return line fitting 34. The particles are then collected from the return line in a conventional manner prior to the water being cooled again and recirculated through the water box 28.
• an exemplary thermoplastic plastic material such as flexible polyvinyl chloride, is generally heated in the extruder to a temperature of about 163 degrees Celsius.
• the plastic temperature is increased about 10 degrees Celsius to about 191 degrees.
• boundary layer flow dictates that the flow of the plastic material in the center of the die holes 42 travels at a rate faster than the flow of the plastic material adjacent the die plate surface defining dies holes 42. Consequently, as a result of the differences in relative velocities, the profile of the plastic material initially exiting the die holes 42 will take on a curved outer surface, such as that of a hemisphere.
• a blade on the multibladed cutter 18 then severs the portion of the extrudate which has exited the face 30 of the die plate 46 of die 12, to create an individual particle.
• the beads may be heated to form a distinct ring structure around a portion of the bead as shown in FIG. 2. By heating the bead, the stress and strain induced into the particle from the severing action of the multibladed cutter 18 during the forming of the bead is apparently released.
• the ring structure noted herein is no longer present in favor of a viscous fluid state. It has been found that the ring structure may be preserved after formation by cooling the particle. Specifically, polyvinyl chloride particles heated to 93° C were instantaneously cooled with water at a temperature of 16° C. Alternatively, the beads were cooled with ambient air at a temperature of 24° C. With this ring structure geometry, the particles may be used as a raw material form for future plastic molding processes.
• the particle may also be used as a decorative device for jewelry such as a beaded necklace, entertainment devices such as kaleidoscopes, or artistic devices such as candles and bead towers. Attention is next directed to FIG. 2 which provides an actual photomicrograph of the particle herein containing an integral protruding ring section.
• FIG. 3 provides a schematic view of a plastic particle 80 containing a continuous integral protruding ring 82 disposed on its surface. In accordance with the present invention, ring 82 has been found to protrude about 0.00508 millimeters from the surface of particle 80.
• FIG. 4 illustrated is particle 80 containing non-continuous ring structure 84 on the surface thereof.
• protrusion falls in the range of about 0.00508 - 0.0127 millimeters.
• protrusions between 0.00508 - 0.0254 millimeters are contemplated, including 0.00254 millimeter increments therebetween.
• the use of plastic particles which form a ring structure upon heating will be particularly advantageous in those plastic molding processes where a solid plastic particle is applied directly to a forming surface, such as roto- casting or slush molding. In slush molding as shown in FIG. 5, an excess charge of material is placed in a charge or powder box 60.
• the box 60 is connected to a mold 62 having a cavity 24 formed in part by a molding surface 66 heated or cooled by a suitable heater 68 or air cooling system 70. Once the box 60 is connected to the mold 62, the box 60 and mold 62 are inverted so that the excess charge of materials is dumped into the mold cavity 64.
• Typical slush molding apparatus is set forth in U.S. Pat. Nos. 4,722,678, 4,878,827 and 5,046,941 all owned by the assignee of the present invention and incorporated by reference. The aforesaid United States Patents include maintaining a static head of material over the layer of material that is dumped onto the molding surface 66 of the mold cavity 64.
• the heating system 68 provides heated air (other suitable heaters are suitable for use with the invention such as the hot oil heater of U.S. Pat. No. 4,389,177 or electrical heaters as shown in U.S. Pat. No. 4,979,888).
• the molding surface 66 is heated to cause the plastic particles to melt as they contact the molding surface 66 and are compacted thereon by the static head of the overlying material.
• the mold cavity 64 is cooled by suitable air cooling or liquid cooling systems as shown in U.S. Pat. Nos. 4,621,995, 4,623,503 and 5,106,285, all owned by the assignee of the present invention and incorporated by reference.
• the shell is concurrently cooled and the powder box 60 and mold cavity 64 are separated so that the mold 62 is opened to remove the shell.
• a suitable example herein of slush molding as set forth above includes PVC beads containing the aforementioned ring structure, at the following compositional distribution: 52.5%> PVC resin, 31.5% plasticizers, 9.3% stabilizers, 1.5% pigment and 4.5% flow aids (all % by weight), and further having a diameter of from 0J78 millimeters to 1.016 millimeters.
• the process involved placing a charge of such beads greater than the weight of the finished product in a charge box and dumping the contents of the charge box into a mold cavity; heating the casting surface to melt a layer of beads that contact the casting surface and flowing the material into a shape corresponding to the heated casting surface; thereafter cooling the molded part and removing it from the mold.
• Roto-casting e.g.
• rotational casting and rotational molding differs from slush molding in that a charge of such beads corresponding to the weight of the product to be molded is placed in a closed hollow heated mold, followed by centrifugally melt flowing the material into a shape corresponding to the heated mold surface; thereafter cooling the centrifugally molded part and removing it from the closed hollow heated mold.
• the use of beads which form a ring structure upon heating are believed particularly advantageous in slush molding and roto-casting as a flow aid into the interstices between the molding particles. That is, slush molding with dry particles and the associated void interstices therebetween can result in molded articles which exhibit porosity.
• plastic materials in addition to the use of polyvinyl chloride include, but are not limited to thermoplastics such as polyurethane, polyolefins (e.g. polypropylene, polyethylene), polystryene and polyester. Still other plastic materials include thermoset materials.

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• 2000
  • 2000-10-11 US US09/685,444 patent/US6632525B1/en not_active Expired - Lifetime
• 2001
  • 2001-10-11 DE DE60122363T patent/DE60122363T2/de not_active Expired - Lifetime
  • 2001-10-11 WO PCT/US2001/042683 patent/WO2002030670A1/en active IP Right Grant
  • 2001-10-11 AU AU2002224452A patent/AU2002224452A1/en not_active Abandoned
  • 2001-10-11 AT AT01986639T patent/ATE336373T1/de not_active IP Right Cessation
  • 2001-10-11 EP EP01986639A patent/EP1332048B1/de not_active Expired - Lifetime

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